WO2023210218A1

WO2023210218A1 - Lubricating oil composition

Info

Publication number: WO2023210218A1
Application number: PCT/JP2023/011484
Authority: WO
Inventors: 仁小松原; 勉高橋
Original assignee: Ｅｎｅｏｓ株式会社
Priority date: 2022-04-26
Filing date: 2023-03-23
Publication date: 2023-11-02
Also published as: JP2023161722A

Abstract

In order to provide a lubricating oil composition which has low viscosity but improves extreme pressure resistance, wear resistance, and fatigue resistance, which have a tendency to worsen with a reduction in the viscosity of a lubricating oil, and is also able to satisfy the wet clutch performance required in a transmission while suppressing a reduction in oxidative stability, the present invention contains a lubricating base oil comprising a mineral base oil and/or a synthetic base oil, (A) a thiadiazole compound, (B) a sulfur-free phosphorus compound, (C) a calcium detergent comprising a calcium phenate detergent, (D) a succinimide dispersant comprising a boron-containing succinimide dispersant, and (E) an oiliness agent-based friction modifier, and has a sulfur content of at most 0.050 mass%, a boron content of less than 0.030 mass%, a kinematic viscosity at 100°C of at most 6.2 mm2/s, a mass ratio MS/MP of the sulfur content MS to the phosphorus content MP of at most 1.00, and a mass ratio MB/MCa of the boron content MB to the calcium content MCa of 0.80-1.20.

Description

lubricating oil composition

The present invention relates to a lubricating oil composition, and more particularly, it is suitably used for lubricating a transmission having a wet clutch such as a wet multi-disc clutch, particularly an automatic transmission having a wet clutch or a continuously variable transmission having a wet clutch. The present invention relates to a lubricating oil composition that can be used as a lubricating oil composition.

One way to save energy in gear devices such as transmissions and final reducers is to reduce the viscosity of lubricating oil. For example, transmissions and final reduction gears have gear bearing mechanisms, and by lowering the viscosity of the lubricating oil used in these, stirring resistance and drag torque caused by the viscous resistance of the lubricating oil can be reduced. It is thought that the power transmission efficiency will be improved, and as a result, it will be possible to improve fuel efficiency.

Japanese Patent Application Publication No. 2014-196396 International Publication No. 2014/142231 Special Publication No. 2021-515061 Special Publication No. 2020-531618 JP 2021-147521 Publication JP 2021-147517 Publication Japanese Patent Application Publication No. 2020-111736 Japanese Patent Application Publication No. 2011-132551 Patent No. 4822684

In general, reducing the viscosity of lubricating oil improves fuel efficiency, but as the oil film thickness decreases, lubrication performance such as extreme pressure properties, wear resistance, and fatigue resistance tends to decrease. . As a means to compensate for or improve the performance of lubricating oil, which decreases as the viscosity of the lubricating oil decreases, extreme pressure agents such as sulfur-based additives, phosphorus-based additives, and phosphorus-sulfur additives and/or anti-wear additives are used. It is conceivable to additionally incorporate an additive that functions as an agent or to increase its content. However, adding or increasing the amount of these additives causes new problems, which in turn worsens the oxidation stability of the lubricating oil, which worsens the friction properties of wet clutches. Therefore, there remains a need to solve the problems associated with lowering the viscosity of lubricating oils.

Although the present invention has a low viscosity, it improves extreme pressure properties, wear resistance, and fatigue resistance, which tend to deteriorate as the viscosity of lubricating oil decreases, and also suppresses deterioration in oxidation stability. It is an object of the present invention to provide a lubricating oil composition that can also satisfy the wet clutch performance required for machines.

The present invention includes the embodiments [1] to [11] below.
[1] A lubricating base oil comprising one or more mineral base oils, one or more synthetic base oils, or a combination thereof;
(A) one or more thiadiazole compounds;
(B) one or more sulfur-free phosphorus compounds;
(C) one or more calcium-based detergents, including one or more calcium phenate detergents;
(D) one or more succinimide dispersants, including one or more boron-containing succinimide dispersants;
(E) one or more oil-based friction modifiers;
Contains
The sulfur content in the composition is 0.050% by mass or less based on the total amount of the composition,
The boron content in the composition is less than 0.030% by mass based on the total amount of the composition,
The kinematic viscosity at 100°C of the composition is 6.2 mm ² /s or less,
The ratio MS/MP of the sulfur content MS (unit: mass %) in the composition to the phosphorus content MP (unit: mass %) in the composition is 1.00 or less,
The ratio MB/MCa of the boron content MB (unit: mass %) in the composition to the calcium content MCa (unit: mass %) in the composition is 0.80 to 1.20. A lubricating oil composition characterized by:

[2] The lubricating oil composition according to [1], wherein the content of the component (A) is 0.010 to 0.050% by mass as a sulfur content based on the total amount of the composition.

[3] The lubricating oil composition according to [1] or [2], wherein the content of the component (B) is 0.010 to 0.100% by mass as a phosphorus content based on the total amount of the composition.

[4] The lubricating oil according to any one of [1] to [3], wherein the boron content MB in the composition is 0.010% by mass or more and less than 0.030% by mass based on the total amount of the composition. Composition.

[5] The lubricating oil composition according to any one of [1] to [4], wherein the content of the component (C) is 0.008 to 0.040% by mass as calcium content based on the total amount of the composition. .

[6] The lubricant according to any one of [1] to [5], wherein the content of component (D) is 0.010% by mass or more and less than 0.030% by mass as boron content based on the total amount of the composition. oil composition.

[7] Component (E) comprises (E1) one or more aliphatic hydrocarbyl groups having 8 to 30 carbon atoms and/or one or more aliphatic hydrocarbyl carbonyl groups having 8 to 30 carbon atoms; amide bond and/or one or more imide bond in one molecule, and the aliphatic hydrocarbyl carbonyl group may constitute a part of the amide bond and/or imide bond. The lubricating oil composition according to any one of [1] to [6], which contains 0.10 to 3.00% by mass of the N-acylated nitrogen-containing compound based on the total amount of the composition.

[8] The lubricating oil composition according to any one of [1] to [7], further comprising (F) one or more poly(meth)acrylates having a weight average molecular weight of 10,000 to 100,000.

[9] (G) Contains 0.10 to 1.00% by mass of one or more amine antioxidants and/or one or more phenolic antioxidants based on the total amount of the composition, [1 ] to [8]. The lubricating oil composition according to any one of [8].

[10] The lubricating oil composition according to any one of [1] to [9], wherein the lubricating base oil has a kinematic viscosity at 100° C. of 4.2 mm ² /s or more and a viscosity index of 120 or more.

[11] The lubricating oil composition according to any one of [1] to [10], wherein the lubricating oil composition has a viscosity index of 155 or more.

[12] In a lubricating oil shear stability test in accordance with JPI-5S-29-88, the lubricating oil composition was irradiated with ultrasonic waves with a frequency of 10 kHz and a vibrator amplitude of 28 μm for 10 hours. The lubricating oil composition according to any one of [1] to [11], which has a kinematic viscosity at °C of 5.5 mm ² /s or more.

[13] The lubricating oil composition according to any one of [1] to [12], which is used for lubrication of a transmission equipped with a wet clutch.

According to the present invention, although the viscosity is low, the extreme pressure properties, wear resistance, and fatigue resistance, which tend to deteriorate as the viscosity of lubricating oil decreases, are improved, and the decline in oxidation stability is suppressed. , it is possible to provide a lubricating oil composition that can also satisfy the wet clutch performance required for transmissions.

The present invention will be explained in detail below. In this specification, unless otherwise specified, the notation "A to B" for numerical values A and B is equivalent to "above A and below B". In such a notation, if a unit is attached only to the numerical value B, the unit shall also be applied to the numerical value A. In this specification, the words "or" and "or" shall mean a logical sum unless otherwise specified. In this specification, the expression "E ₁ and/or E ₂ " with respect to elements E ₁ and E ₂ is equivalent to "E ₁ or E ₂ , or a combination thereof", and N elements E ₁ ,... , E _i , ..., E _N (N is an integer of 3 or more), the notation "E ₁ , ..., and/or E _N " means "E ₁ , ..., or E _i , ..., or E _N , or a combination thereof" (i is a variable that takes all integers satisfying 1<i<N.). Further, in this specification, "alkaline earth metal" includes magnesium.

In this specification, unless otherwise specified, the content of each element of calcium, magnesium, zinc, phosphorus, sulfur, boron, barium, and molybdenum in oil is determined by inductively coupled plasma emission spectroscopy in accordance with JIS K0116. It shall be measured by an analytical method (intensity ratio method (internal standard method)). Further, the content of nitrogen element in the oil shall be measured by chemiluminescence method in accordance with JIS K2609. Moreover, in this specification, "weight average molecular weight" means a weight average molecular weight measured by gel permeation chromatography (GPC) in terms of standard polystyrene. The measurement conditions for GPC are as follows.
[GPC measurement conditions]
Equipment: ACQUITY (registered trademark) APC UV RI system manufactured by Waters Corporation Column: From the upstream side, ACQUITY (registered trademark) APC XT900A manufactured by Waters Corporation (gel particle size 2.5 μm, column size (inner diameter x length) 4.6 mm x 150 mm) and one ACQUITY (registered trademark) APC XT200A (gel particle size 2.5 μm, column size (inner diameter x length) 4.6 mm x 150 mm) manufactured by Waters Corporation are connected in series. Column temperature: 40 ℃
Sample solution: Tetrahydrofuran solution with sample concentration of 1.0% by mass Eluent: Tetrahydrofuran solution Injection volume: 20.0 μL
Detection device: Differential refractive index detector Reference material: Standard polystyrene (Agilent EasiCal (registered trademark) PS-1 manufactured by Agilent Technologies) 8 points (molecular weight: 2698000, 597500, 290300, 133500, 70500, 30230, 9590, 2970 )
If the weight average molecular weight measured under the above conditions is less than 10,000, the column and reference material are changed to the following conditions and the measurement is performed again.
Column: From the upstream side, one ACQUITY (registered trademark) APC XT125A manufactured by Waters Corporation (gel particle size 2.5 μm, column size (inner diameter x length) 4.6 mm x 150 mm), and ACQUITY (registered trademark) manufactured by Waters Corporation. (trademark) APC XT45A (gel particle size 1.7 μm, column size (inner diameter x length) 4.6 mm x 150 mm) connected in series Reference material: standard polystyrene (Agilent EasiCal (registered trademark) manufactured by Agilent Technologies PS- 1) 10 points (molecular weight: 30230, 9590, 2970, 890, 786, 682, 578, 474, 370, 266)

<Lubricant base oil>
The lubricating oil composition of the present invention (hereinafter sometimes referred to as "lubricating oil composition" or "composition") contains a major amount of lubricating base oil and one or more additives other than the base oil. Contains. In the lubricating oil composition of the present invention, the lubricating oil base oil used is a lubricating oil base oil comprising one or more mineral base oils, one or more synthetic base oils, or a combination thereof.

As the lubricating base oil, one or more mineral oil base oils, one or more synthetic base oils, or a mixture thereof can be used. In one embodiment, the lubricant base oil includes Group I base oil of the API base oil classification (hereinafter sometimes referred to as "API Group I base oil"), Group II base oil (hereinafter referred to as "API Group II base oil"), ), Group III base oils (hereinafter sometimes referred to as "API Group III base oils"), Group IV base oils (hereinafter sometimes referred to as "API Group IV base oils"). ), Group V base oil (hereinafter sometimes referred to as "API Group V base oil"), or a mixed base oil thereof can be used. API Group I base oil is a mineral oil base oil with a sulfur content of more than 0.03% by mass and/or a saturated content of less than 90% by mass, and a viscosity index of 80 or more and less than 120. API Group II base oil is a mineral oil base oil having a sulfur content of 0.03% by mass or less, a saturated content of 90% by mass or more, and a viscosity index of 80 or more and less than 120. API Group III base oil is a mineral oil base oil having a sulfur content of 0.03% by mass or less, a saturated content of 90% by mass or more, and a viscosity index of 120 or more. API Group IV base oils are polyalpha-olefin base oils. API Group V base oils are base oils other than the above Groups I to IV, and preferred examples include ester base oils.

In one embodiment, component (A) includes one or more API Group II base oils, one or more API Group III base oils, one or more API Group IV base oils, or one or more API Group IV base oils. V base oils or combinations thereof can be preferably used.

Examples of mineral oil base oils include lubricating oil fractions obtained by atmospheric distillation and/or vacuum distillation of crude oil, which can be subjected to solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, and hydrogen dewaxing. Examples include paraffinic base oils refined by one or a combination of two or more selected from chemical refining, sulfuric acid washing, clay treatment, etc., normal paraffinic base oils, isoparaffinic base oils, and mixtures thereof. be able to. API Group II and Group III base oils are typically produced via a hydrocracking process.

The % _CP of the mineral base oil is preferably 60 or more, more preferably 65 or more from the viewpoint of further improving the viscosity-temperature characteristics and fuel efficiency of the composition, and is also preferably from the viewpoint of improving the solubility of additives. is 99 or less, more preferably 95 or less, even more preferably 94 or less, and in one embodiment may be 60-99, or 60-95, or 65-95, or 65-94.

The % _CA of the mineral base oil is preferably 2 or less, more preferably 1 or less, still more preferably 0.8 or less, particularly preferably 0. 5 or less.

The % _CN of the mineral base oil is preferably 1 or more, more preferably 4 or more from the viewpoint of increasing the solubility of additives, and is also preferably from the viewpoint of further improving the viscosity-temperature characteristics and fuel efficiency of the composition. is 40 or less, more preferably 35 or less, and in one embodiment may be 1-40, or 4-35.

In this specification, %C _P , %C _N and %C _A are the percentages of the number of paraffin carbons to the total number of carbons, respectively, determined by a method based on ASTM D 3238-85 (ndM ring analysis). , means the percentage of naphthenic carbon number to total carbon number, and the percentage of aromatic carbon number to total carbon number. In other words, the preferred ranges of % _CP , % _CN and % _CA mentioned above are based on the values determined by the above method.For example, even if the lubricant base oil does not contain naphthenes, %C _N can have a value greater than zero.

From the viewpoint of improving the viscosity-temperature characteristics of the composition, the content of saturated components in the mineral base oil is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 99% by mass, based on the total amount of the base oil. % by mass or more. Note that in this specification, the saturated content means a value measured in accordance with ASTM D 2007-93.

The aromatic content in the mineral base oil is preferably 0 to 10% by mass, more preferably 0 to 5% by mass, particularly preferably 0 to 1% by mass, based on the total amount of the base oil. In embodiments, it may be 0.1% by mass or more. By keeping the aromatic content below the above upper limit, it is possible to improve the low-temperature viscosity characteristics and viscosity-temperature characteristics in the fresh oil state, and it is also possible to further improve fuel efficiency. , it becomes possible to reduce evaporation loss of lubricating oil and reduce consumption of lubricating oil. Moreover, when an additive is blended into the lubricating base oil, it becomes possible to effectively exhibit the effectiveness of the additive. Furthermore, the lubricating base oil may not contain aromatic components, but when the aromatic component content is at least the above lower limit, the solubility of the additive can be improved.

Note that in this specification, the aromatic content means a value measured in accordance with ASTM D 2007-93. Aromatic components usually include alkylbenzenes, alkylnaphthalenes, anthracene, phenanthrene, and their alkylated products, as well as compounds in which four or more benzene rings are condensed, pyridines, quinolines, phenols, naphthols, etc. This includes aromatic compounds having heteroatoms.

Examples of API Group IV base oils include those having 2 to 32 carbon atoms, preferably 6 carbon atoms, such as ethylene-propylene copolymers, polybutenes, 1-octene oligomers, 1-decene oligomers, and hydrogenated products thereof. Mention may be made of oligomers and cooligomers of α-olefins of ~16 and their hydrogenation products.

Preferred examples of API Group V base oils include monoesters (e.g. butyl stearate, octyl laurate, 2-ethylhexyl oleate, etc.); diesters (e.g. ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate, etc.); polyesters (e.g., trimellitic acid ester, etc.); polyol esters (e.g., trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, pentaerythritol) Examples include ester base oils such as pelargonate, etc.). Other examples of API Group V base oils include aromatic synthetic base oils such as alkylbenzenes, alkylnaphthalenes, polyoxyalkylene glycols, dialkyl diphenyl ethers, polyphenyl ethers, and the like.

The kinematic viscosity at 40° C. of the lubricating base oil (all base oils) is preferably 40 mm ² /s or less, 30 mm ² /s or less, or 22 mm from the viewpoint of energy saving and improving the low-temperature viscosity characteristics of the lubricating oil composition. ² /s or less. Note that in this specification, "kinematic viscosity at 40°C" refers to a kinematic viscosity measured in accordance with JIS K 2283-2000 using an automatic viscometer (trade name "CAV-2100", manufactured by Cannon Instrument Co., Ltd.) as a measuring device. Means kinematic viscosity at 40°C.

The kinematic viscosity at 100° C. of the lubricating base oil (all base oils) is preferably 6.0 mm ² /s or less, or 5.5 mm ² /s from the viewpoint of further improving energy saving and low-temperature viscosity characteristics of the lubricating oil composition. or 5.0 mm ² /s or less, and preferably 3.5 mm ² /s or more, 4.0 mm ² /s or more, or 4.2 mm ² /s from the viewpoint of improving wear resistance and seizure resistance. s or more, and in one embodiment, 3.5 to 6.0 mm ² /s, or 4.0 to 5.5 mm ² /s, or 4.0 to 5.0 mm ² /s, or 4.2 to 5.0 mm ² /s. Note that in this specification, "kinematic viscosity at 100°C" refers to a kinematic viscosity measured in accordance with JIS K 2283-2000 using an automatic viscometer (trade name "CAV-2100", manufactured by Cannon Instrument) as a measuring device. Means kinematic viscosity at 100°C.

The viscosity index of the lubricating base oil (all base oils) is preferably 100 or more, more preferably 105 or more, from the viewpoint of improving the viscosity-temperature characteristics of the composition and further improving fuel efficiency and wear resistance. More preferably, it is 110 or more, particularly preferably 115 or more, and most preferably 120 or more. In this specification, the viscosity index refers to the viscosity index measured using an automatic viscometer (trade name "CAV-2100", manufactured by Cannon Instrument Co., Ltd.) as a measuring device in accordance with JIS K 2283-2000. means.

The pour point of the lubricating base oil (all base oils) is preferably -10°C or lower, more preferably -12.5°C or lower, and even more preferably -15°C or lower, from the viewpoint of low-temperature fluidity of the entire lubricating oil composition. , particularly preferably -17.5°C or lower, most preferably -20.0°C or lower. Note that in this specification, pour point means a pour point measured in accordance with JIS K 2269-1987.

The sulfur content in the base oil depends on the sulfur content of its raw material. For example, when a substantially sulfur-free raw material such as a synthetic wax component obtained by Fischer-Tropsch reaction or the like is used, a substantially sulfur-free base oil can be obtained. Further, when using raw materials containing sulfur such as slack wax obtained in the base oil refining process or microwax obtained in the refining process, the sulfur content in the obtained base oil is usually 100 mass ppm or more. The sulfur content in the lubricating base oil (total base oil) is usually 0.03% by mass or less, and preferably 0.01% by mass or less from the viewpoint of oxidation stability. In this specification, the sulfur content in the base oil means the amount of sulfur measured in accordance with JIS K 2541-2003.

In one embodiment, the lubricant base oil is one or more API Group II base oils, one or more API Group III base oils, one or more API Group IV base oils, or one or more API Group V base oils. The base oil, or a combination thereof, may comprise 80 to 100% by weight, or 90 to 100% by weight, or 95 to 100% by weight, or 98 to 100% by weight based on the total amount of base oil. In one embodiment, the lubricant base oil is based on one or more API Group II base oils, one or more API Group III base oils, or one or more API Group IV base oils, or combinations thereof. It may contain 80 to 100% by mass, or 90 to 100% by mass, or 95 to 100% by mass, or 98 to 100% by mass based on the total amount of oil. Although the lubricant base oil may or may not contain an API Group V base oil, the content of one or more API Group V base oils in the lubricant base oil may, in one embodiment, From the viewpoint of improving oxidation stability, it may preferably be 0 to 50% by mass, or 0 to 20% by mass, or 0 to 10% by mass based on the total amount of base oil.

The content of the lubricating base oil (total base oil) in the lubricating oil composition is usually 60% by mass or more based on the total amount of the lubricating oil composition, and in one embodiment, 85 to 98.5% by mass, or 90% by mass. 98.5% by weight, or 93-97% by weight.

<(A) Thiadiazole compound>
The lubricating oil composition of the present invention contains (A) one or more thiadiazole compounds (hereinafter sometimes referred to as "component (A)"). As component (A), one type of thiadiazole compound may be used alone, or two or more types of thiadiazole compounds may be used in combination.

Examples of component (A) include 1,3,4-thiadiazole represented by the following general formula (1), 1,2,4-thiadiazole compound represented by the following general formula (2), and the following general formula Examples include 1,2,3-thiadiazole compounds represented by (3).

(In general formulas (1) to (3), R ¹ and R ² may be the same or different, and each independently represents a hydrogen atom or a carbon number of 1 to 20 (preferably 6 to 18, or 9 to 12, e.g. 9) represents a hydrocarbyl (preferably alkyl) group; a and b may be the same or different, and each independently represents an integer from 0 to 8.)

Component (A) is represented by any of the above general formulas (1) to (3), a and b are 2, and R ¹ and R ² are each independently an alkyl group having 6 to 18 carbon atoms. Certain bis(alkyldithio)thiadiazole compounds can be particularly preferably used. The number of carbon atoms in the alkyl group may be 9 to 12, or 9 in one embodiment. In one embodiment, such bis(alkyldithio)thiadiazole compounds may be used in combination with mono(alkyldithio)thiadiazole compounds. The mono(alkyldithio)thiadiazole compound is represented by any of the general formulas (1) to (3), and one of -S _a -R ¹ group and -S _b -R ² groups has 6 to 18 carbon atoms. Mono(alkyldithio)thiadiazole compounds in which one is an alkyldithio group and the other is an -SSH group or a -SH group are preferred. The preferred carbon number of the alkyl group is the same as that of the bis(alkyldithio)thiadiazole compound.

The content of component (A) in the lubricating oil composition is 0.050 as a sulfur content based on the total amount of the composition, from the viewpoint of increasing the transmission torque capacity and engagement performance of the wet clutch, and from the viewpoint of increasing the wear resistance of the gear. It is not more than 0.045% by mass, or preferably not more than 0.040% by mass. The content of component (A) is determined from the viewpoint of further increasing the wear resistance and fatigue resistance of gears, and the oxidation stability of lubricating oil, and from the viewpoint of further increasing transmission torque capacity and engagement performance of wet clutches. The sulfur content is preferably 0.010% by mass or more based on the total amount. In one embodiment, the content of component (A) is 0.010 to 0.050 mass %, or 0.010 to 0.045 mass %, or 0.010 to 0. .040% by weight.

<(B) Sulfur-free phosphorus compound>
The lubricating oil composition of the present invention contains (B) one or more sulfur-free phosphorus compounds (hereinafter sometimes referred to as "component (B)"). As component (B), one type of phosphorus compound may be used alone, or two or more types of phosphorus compounds may be used in combination.

Preferred examples of component (B) include a compound represented by the following general formula (4), a compound represented by the following general formula (5), and a phosphorous acid monoester represented by the following general formula (4). and metal salts and ammonium salts of phosphoric acid partial esters represented by the following general formula (5).

(In general formula (4), R ³ represents a hydrocarbon group having 1 to 30 carbon atoms; R ⁴ represents a hydrocarbon group having 1 to 30 carbon atoms or a hydrogen atom; R ³ and R ⁴ may be the same or mutually (The compound of general formula (4) shall include any tautomer thereof.)

(In general formula (5), R ⁵ represents a hydrocarbon group having 1 to 30 carbon atoms; R ⁶ and R ⁷ each independently represent a hydrocarbon group having 1 to 30 carbon atoms or a hydrogen atom; R ⁵ , R ⁶ and R ⁷ may be the same or different.)

Examples of hydrocarbon groups having 1 to 30 carbon atoms in general formulas (4) and (5) include alkyl groups, cycloalkyl groups, alkenyl groups, alkyl-substituted cycloalkyl groups, aryl groups, alkyl-substituted aryl groups, and aryl groups. Examples include alkyl groups. The hydrocarbon group is preferably an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 24 carbon atoms, and in one embodiment, an alkyl group having 3 to 18 carbon atoms, more preferably an alkyl group having 4 to 12 carbon atoms. It is an aryl group or an alkylaryl group.

In one embodiment, a preferable example of the hydrocarbon group is a straight or branched alkyl group having 4 to 18 carbon atoms. Examples of alkyl groups include butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl. The following groups can be mentioned.
Other preferred examples of the hydrocarbon group include aryl groups having 6 to 10 carbon atoms such as phenyl and naphthyl; and alkylaryl groups having 7 to 9 carbon atoms such as tolyl, xylyl and mesityl. can be mentioned.

Examples of metals that form metal salts with the phosphorus compound represented by general formula (4) or (5) include alkali metals such as lithium, sodium, potassium, and cesium, calcium, magnesium, barium, etc. Examples include alkaline earth metals, zinc, copper, iron, lead, nickel, silver, manganese, and other heavy metals. Among these, alkaline earth metals such as calcium and magnesium, zinc, or a combination thereof are preferred.

Examples of nitrogen-containing compounds that form ammonium salts with the phosphorus compound represented by general formula (4) or (5) include ammonia, monoamines, diamines, polyamines, and alkanolamines. More specifically, nitrogen-containing compounds represented by the following general formula (6); alkylene diamines such as methylene diamine, ethylene diamine, propylene diamine, and butylene diamine; diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine; polyamines such as; and combinations thereof.

(In general formula (6), R ⁸ to R ¹⁰ each independently represent a hydrogen atom, a hydrocarbyl group having 1 to 8 carbon atoms, or a hydrocarbyl group having 1 to 8 carbon atoms having a hydroxyl group; R ⁸ to R ¹⁰ At least one of them is a hydrocarbyl group having 1 to 8 carbon atoms, or a hydrocarbyl group having 1 to 8 carbon atoms and having a hydroxyl group.)

As a preferable example of the compound represented by the above general formula (4), in the above general formula (4), R ³ and R ⁴ are each independently an alkyl group having 3 to 18 carbon atoms (preferably 4 to 12), an aryl group, groups (e.g. phenyl group, naphthyl group, etc.), or alkylaryl groups (e.g. methylphenyl group, dimethylphenyl group, trimethylphenyl group (e.g. mesityl group, etc.), isopropylphenyl group, isopropylmethylphenyl group (e.g. thymyl group, etc.) , alkylphenyl groups, etc.). Although R ³ and R ⁴ may be different, it is more preferable that they are the same group.
As a preferable example of the compound represented by the above general formula (5), in the above general formula (5), R ⁵ to R ⁷ are each independently an alkyl group having 3 to 18 carbon atoms (preferably 4 to 12 carbon atoms), an aryl group, groups (e.g. phenyl group, naphthyl group, etc.), or alkylaryl groups (e.g. methylphenyl group, dimethylphenyl group, trimethylphenyl group (e.g. mesityl group, etc.), isopropylphenyl group, isopropylmethylphenyl group (e.g. thymyl group, etc.) , alkylphenyl groups, etc.). Although R ⁵ to R ⁷ may be different from each other, it is more preferable that they are the same group.
These compounds may be used alone or in combination of two or more.

From the viewpoint of further improving wear resistance, seizure resistance, and oxidation stability, the content of component (B) in the lubricating oil composition is preferably 0.010% by mass or more as a phosphorus content based on the total amount of the composition, or 0.025% by mass or more, or 0.030% by mass or more. In addition, the content of component (B) is preferably set as a phosphorus content based on the total amount of the composition, from the viewpoint of further increasing seizure resistance, fatigue resistance, and oxidation stability, and from the viewpoint of further increasing the transmission torque capacity of a wet clutch. It is 0.100% by mass or less, or 0.085% by mass or less, or 0.075% by mass or less. In one embodiment, the content of component (B) is 0.010 to 0.100% by mass, or 0.025 to 0.085% by mass, or 0.030 to 0. .75% by weight.

<(C) Calcium-based cleaning agent>
The lubricating oil composition of the present invention contains (C) one or more calcium-based detergents (hereinafter sometimes referred to as "component (C)"), including one or more calcium phenate detergents. . When component (C) contains a calcium phenate detergent, it becomes possible to increase the transmission torque capacity of the wet clutch. As component (C), one type of calcium-based detergent may be used alone, or two or more types of calcium-based detergents may be used in combination. In addition, component (C) may consist of one or more calcium phenate detergents, and one or more calcium phenate detergents and one or more calcium detergents other than calcium phenate detergents. May contain. Examples of calcium detergents other than calcium phenate detergents include calcium sulfonate detergents, calcium salicylate detergents, and the like.

Examples of calcium phenate detergents include overbased salts of calcium salts of compounds having the structure represented by the following general formula (7).

In the general formula (7), R ¹¹ represents a linear or branched, saturated or unsaturated alkyl or alkenyl group having 6 to 21 carbon atoms, m represents an integer of 0 to 9, and A represents sulfide (-S -) group or methylene (-CH ₂ -) group, and x represents an integer of 1 to 3. Note that R ¹¹ may be a combination of two or more different groups, and x may be a combination of a plurality of different integers. When A is a methylene group, x is preferably 1. The substitution position of the -A _x - group on each aromatic ring is typically the o-position or the p-position relative to the hydroxy group, typically the o-position.

The number of carbon atoms in R ¹¹ in general formula (7) is preferably 9 or more from the viewpoint of increasing solubility in base oil, and preferably 18 or less, more preferably 15 or less from the viewpoint of ease of production. In embodiments of 9-18, or 9-15.

m in general formula (2) is preferably 0 to 3.

Preferred examples of calcium sulfonate detergents include calcium salts of alkyl aromatic sulfonic acids obtained by sulfonating an alkyl aromatic compound, or basic salts or overbased salts thereof. The weight average molecular weight of the alkyl aromatic compound is preferably 400 to 1,500, more preferably 700 to 1,300.
Examples of alkyl aromatic sulfonic acids include so-called petroleum sulfonic acids and synthetic sulfonic acids. Examples of petroleum sulfonic acids include those obtained by sulfonating an alkyl aromatic compound of a lubricating oil fraction of mineral oil, and so-called mahogany acid, which is a by-product during the production of white oil. Examples of synthetic sulfonic acids include straight-chain or branched alkyls obtained by recovering by-products in alkylbenzene manufacturing plants, which are raw materials for detergents, or by alkylating benzene with polyolefins. Examples include sulfonated alkylbenzenes having groups. Other examples of synthetic sulfonic acids include sulfonated alkylnaphthalenes such as dinonylnaphthalene. Further, the sulfonating agent for sulfonating these alkyl aromatic compounds is not particularly limited, and for example, fuming sulfuric acid or sulfuric anhydride can be used.

Examples of calcium salicylate detergents include calcium salicylate or its basic or overbased salts. A preferred example of calcium salicylate is calcium salicylate represented by the following general formula (8).

In general formula (8), R ¹² each independently represents an alkyl or alkenyl group having 14 to 30 carbon atoms (preferably 14 to 24, or 14 to 20, or 14 to 18), and a represents 1 or 2. , preferably 1. Note that when a=2, R ¹² may be a combination of different groups.

One preferred form of the calcium salicylate-based detergent is calcium salicylate, or a basic salt or overbased salt thereof, where a=1 in the above general formula (8).

The method for producing calcium salicylate is not particularly limited, and known methods for producing monoalkyl salicylate can be used. For example, monoalkyl salicylic acid obtained by using phenol as a starting material, alkylation using an olefin, and then carboxylating with carbon dioxide gas, or alkylating using an equivalent amount of the above olefin using salicylic acid as a starting material, The obtained monoalkyl salicylic acid, etc. is reacted with a metal base such as a calcium oxide or hydroxide, or the monoalkyl salicylic acid, etc. is converted into an alkali metal salt such as a sodium salt or a potassium salt, and then converted into a calcium salt. Calcium salicylate can be obtained by metal exchange with.

The method for obtaining overbased calcium phenate, sulfonate, or salicylate is not particularly limited, but for example, calcium phenate, sulfonate, or salicylate is converted to a calcium base such as calcium hydroxide in the presence of carbon dioxide gas. An overbased calcium phenate, sulfonate, or salicylate can be obtained by reacting with.

The base number of component (C) is not particularly limited, but is preferably 50 to 500 mgKOH/g, more preferably 100 to 400 mgKOH/g, particularly preferably 200 to 350 mgKOH/g. Note that in this specification, the base number means the base number measured by the perchloric acid method in accordance with ASTM D 2896.

The content of component (C) in the lubricating oil composition is determined based on the total amount of the composition, from the viewpoint of further improving wear resistance, seizure resistance, oxidation stability, and the transmission torque capacity and engagement performance of the wet clutch. The calcium content is preferably 0.008% by mass or more, 0.009% by mass or more, or 0.010% by mass or more. In addition, the content of component (C) is determined based on the total amount of the composition, from the viewpoint of making it easier to reduce the ratio MB/MCa of boron content (MB) to calcium content (MCa) in the composition to be below the upper limit. The calcium content is preferably 0.040% by mass or less, 0.038% by mass or less, or 0.036% by mass or less on a standard basis. In one embodiment, the content of component (C) is 0.008 to 0.040% by mass, or 0.009 to 0.040% by mass, or 0.010 to 0.010% by mass as calcium content based on the total amount of the composition. It can be .040% by weight, or 0.009-0.038% by weight, or 0.010-0.036% by weight.

Component (C) may include only one or more calcium phenate detergents, or one or more calcium-based detergents other than calcium phenate detergents (e.g., calcium sulfonate detergents, calcium phenate detergents, etc.). ) may further be included. However, from the perspective of further increasing the transmission torque capacity of wet clutches, the ratio of phenate to the total soap base of component (C), that is, the ratio of phenate to the mass of the total soap base of component (C) in terms of organic acid, The mass ratio of all soap groups of the agent in terms of organic acid is preferably 65 to 100% by mass, more preferably 80 to 100% by mass, even more preferably 90 to 100% by mass, and in one embodiment, 95 to 100% by mass. It can be up to 100% by weight. As used herein, the soap group of a metal-based detergent refers to the conjugate base of the organic acid that constitutes the soap component of the metal-based detergent (for example, an alkyl salicylate anion in the case of a salicylate detergent, and an alkyl salicylate anion in the case of a sulfonate detergent). For example, it means an alkylbenzene sulfonate anion, and in the case of a phenate detergent, an alkyl phenate anion. In general, in the lubricating oil field, metal detergents include organic acid metal salts that can form micelles in the base oil (for example, alkali or alkaline earth metal alkyl salicylates, alkali or alkaline earth metal alkylbenzene sulfonates, and alkali or alkaline earth metal alkyl phenates, etc.), or the organic acid metal salt and basic metal salt (for example, the hydroxide, carbonate, boron of the alkali or alkaline earth metal constituting the organic acid metal salt) (acid acid, etc.) is used. Such organic acids usually contain at least one polar group with Brønsted acidity capable of forming salts with metal bases (e.g., carboxy group, sulfo group, phenolic hydroxy group, etc.) and a straight or branched alkyl group. (For example, a linear or branched alkyl group having 6 or more carbon atoms, etc.) in one molecule.

<(D) Succinimide dispersant>
The lubricating oil composition of the present invention includes (D) one or more boron-containing succinimide dispersants (hereinafter sometimes referred to as "component (D)"). Contains. When the component (D) contains a boron-containing succinimide dispersant, it becomes possible to improve wear resistance and seizure resistance, and to increase the transmission torque capacity of a wet clutch. As component (D), one type of succinimide dispersant may be used alone, or two or more types of succinimide dispersants may be used in combination. Component (D) may also consist of one or more boron-containing succinimide dispersants, one or more boron-containing succinimide dispersants, and one or more boron-free succinimide dispersants. May contain.

Preferred examples of the succinimide ashless dispersant include succinimide and/or modified succinimide having at least one alkyl group or alkenyl group in the molecule.

Examples of succinimides having at least one alkyl group or alkenyl group in the molecule include compounds represented by the following general formula (9) or (10).

In the general formula (9), R ¹³ represents an alkyl group or alkenyl group having 40 to 400 carbon atoms, and d represents an integer of 1 to 5, preferably 2 to 4. The carbon number of ^R13 is preferably 40 or more, more preferably 60 or more from the viewpoint of solubility in the lubricating oil base oil, and preferably 400 or less, more preferably more preferably from the viewpoint of improving the low temperature fluidity of the lubricating oil composition. 350 or less, and in one embodiment may be from 40 to 400, or from 60 to 350. R ¹³ is particularly preferably a polybutenyl group.

In general formula (10), R ¹⁴ and R ¹⁵ each independently represent an alkyl group or alkenyl group having 40 to 400 carbon atoms, and may be a combination of different groups. Further, e represents an integer of 0 to 4, preferably 1 to 4, more preferably 1 to 3. The number of carbon atoms in R ¹⁴ and R ¹⁵ is preferably 40 or more, more preferably 60 or more from the viewpoint of solubility in the lubricating oil base oil, and preferably 400 or less from the viewpoint of improving the low-temperature fluidity of the lubricating oil composition. More preferably, it is 350 or less, and in one embodiment, it may be 40 to 400, or 60 to 350. R ¹⁴ and R ¹⁵ are particularly preferably polybutenyl groups.

The alkyl group or alkenyl group (R ¹³ to R ¹⁵ ) in formulas (9) and (10) may be linear or branched, and are preferably oligomers of olefins such as propylene, 1-butene, isobutene, etc. Examples include branched alkyl groups and branched alkenyl groups derived from cooligomers of ethylene and propylene. Among these, branched alkyl or alkenyl groups derived from oligomers of isobutene, commonly called polyisobutylene, and polybutenyl groups are most preferred.
The preferred number average molecular weight of the alkyl group or alkenyl group (R ¹³ to R ¹⁵ ) in formulas (9) and (10) is 800 to 3,500, more preferably 1,000 to 3,500.

Succinimide having at least one alkyl group or alkenyl group in its molecule is a so-called mono-type succinic acid represented by the general formula (9), in which succinic anhydride is added to only one end of the polyamine chain. imide and a so-called bis-type succinimide represented by the general formula (10) in which succinic anhydride is added to both ends of a polyamine chain. The lubricating oil composition may contain either mono-type succinimide or bis-type succinimide, or may contain both as a mixture. The content of bis-type succinimide or its derivative (modified product) in component (C) is preferably 50% by mass or more, more preferably 70% by mass based on the total amount of component (C) (100% by mass). % or more.

The method for producing the succinimide having at least one alkyl group or alkenyl group in the molecule is not particularly limited. For example, the above succinimide can be obtained as a condensation reaction product (condensation product) by reacting an alkyl or alkenyl succinic acid or its anhydride having an alkyl group or alkenyl group having 40 to 400 carbon atoms with a polyamine. . Note that alkyl or alkenyl succinic acid or its anhydride can be obtained by reacting a compound having an alkyl group or alkenyl group having 40 to 400 carbon atoms with maleic anhydride at 100 to 200°C. As component (C), the above condensation product may be used as it is, or the above condensation product may be converted into a derivative (modified product) described below. The condensation product of alkyl or alkenyl succinic acid or its anhydride and polyamine may be a bis-type succinimide (see general formula (10)) in which both ends of the polyamine chain are imidized, It may be a monotype succinimide in which only one end of the polyamine chain is imidized (see general formula (9)), or a mixture thereof. Here, examples of polyamines include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and mixtures thereof, and polyamine raw materials containing one or more selected from these are preferably used. be able to. The polyamine raw material may or may not further contain ethylenediamine, but from the viewpoint of improving the performance as a dispersant for the condensation product or its derivative, the content of ethylenediamine in the polyamine raw material It is preferably 0 to 10% by weight, more preferably 0 to 5% by weight based on the total amount. The succinimide obtained as a condensation reaction product of an alkyl or alkenyl succinic acid having an alkyl or alkenyl group having 40 to 400 carbon atoms or an anhydride thereof and a mixture of two or more types of polyamines has the general formula (9). or a mixture of compounds having different d or e in (10).

Component (D) contains one or more boron-containing succinimide dispersants. The boron-containing succinimide dispersant is produced by neutralizing or amidating some or all of the remaining amino groups and/or imino groups by allowing boric acid to act on the unmodified succinimide. It can be obtained as acid-modified succinimide (boron-modified succinimide or boronated succinimide).

Examples of modified succinimides include:
(i) The above-mentioned boron-containing succinimide, that is, a boron-modified succinimide in which some or all of the remaining amino groups and/or imino groups are neutralized or amidated by acting boric acid on the succinimide. Succinimide (boronated succinimide);
(ii) To the above succinimide, a monocarboxylic acid having 1 to 30 carbon atoms such as a fatty acid, a polycarboxylic acid having 2 to 30 carbon atoms (for example, oxalic acid, phthalic acid, trimellitic acid, pyromellitic acid, etc.), By acting with these anhydrides or ester compounds, alkylene oxides having 2 to 6 carbon atoms, or hydroxy(poly)oxyalkylene carbonates, some or all of the remaining amino groups and/or imino groups are neutralized or amidated oxygen-containing organic compound-modified succinimide;
(iii) a phosphoric acid-modified succinimide in which some or all of the remaining amino groups and/or imino groups are neutralized or amidated by allowing phosphoric acid to act on the succinimide;
(iv) a sulfur-modified succinimide obtained by reacting the succinimide with a sulfur compound; and
(v) a modified succinimide obtained by subjecting the succinimide to a combination of two or more modifications selected from modification with an oxygen-containing organic compound, boron modification, phosphoric acid modification, and sulfur modification;
can be mentioned.

The weight average molecular weight of component (D) is preferably 1,000 to 20,000, more preferably 1,000 to 15,000, particularly preferably 2,000 to 9,000. When component (C) contains two or more types of succinimide dispersants, it is preferable that the weight average molecular weight of each succinimide dispersant is within the above range.

The boron content of component (D) in the lubricating oil composition is preferably 0.010 based on the total amount of the composition, from the viewpoint of further improving wear resistance, seizure resistance, and transmission torque capacity of a wet clutch. % by mass or more. Further, the boron content of component (D) is less than 0.030% by mass, preferably 0.029% by mass or less, from the viewpoint of improving fatigue resistance. In one embodiment, the boron content of component (D) may be 0.010% by mass or more and less than 0.030% by mass, or 0.010 to 0.029% by mass based on the total amount of the composition. .

The nitrogen content of component (D) in the lubricating oil composition is preferably 0.030% by mass or more, or 0.03% by mass or more based on the total amount of the composition, from the viewpoint of further increasing oxidation stability (base number maintenance property). It is .035% by mass or more, or 0.040% by mass or more. In addition, the nitrogen content of component (D) is preferably 0.055% by mass or less, or 0.050% by mass based on the total amount of the composition, from the viewpoint of further improving gear lubrication performance (seizure resistance and fatigue resistance). % by mass or less, or 0.045% by mass or less. In one embodiment, the nitrogen content of component (D) is 0.030 to 0.055% by mass, 0.035 to 0.050% by mass, or 0.040 to 0.045% by mass. It can be.

<(E) Oil-based friction modifier>
The lubricating oil composition of the present invention contains one or more oil-based friction modifiers (hereinafter sometimes referred to as "component (E)"). As component (E), one type of oil-based friction modifier may be used alone, or two or more types of oil-based friction modifiers may be used in combination.

Examples of oil-based friction modifiers include compounds having 6 to 50 carbon atoms and containing one or more hetero elements selected from oxygen atoms, nitrogen atoms, and sulfur atoms in the molecule. Preferred examples of the oil-based friction modifier include aliphatic amines, fatty acid amides, fatty acid hydrazides, aliphatic imide compounds, and fatty acids having at least one linear or branched alkyl or alkenyl group having 6 to 30 carbon atoms in the molecule. Examples include group ureas, fatty acid esters, fatty acid metal salts, aliphatic alcohols, aliphatic ethers, and the like.

An example of an amide friction modifier is a fatty acid having 7 to 30 carbon atoms, preferably 8 to 30 carbon atoms, or 10 to 30 carbon atoms, or 12 to 24 carbon atoms, or 12 to 20 carbon atoms, or 12 to 18 carbon atoms, and an aliphatic primary Alternatively, secondary amine compounds, aliphatic primary or secondary alkanolamine compounds, aliphatic polyamines, or condensation products with ammonia (fatty acid amide friction modifiers) can be mentioned.
The aliphatic primary or secondary amine compound preferably has an alkyl or alkenyl group having 1 to 30 carbon atoms, more preferably 1 to 10 carbon atoms, even more preferably 1 to 4 carbon atoms, and has one In embodiments, it has a methyl group or an ethyl group.
The aliphatic primary or secondary alkanolamine compound preferably has an alkylene or alkenylene group having 1 to 30 carbon atoms, more preferably 1 to 10 carbon atoms, even more preferably 1 to 4 carbon atoms, and in embodiments with methylene or ethylene groups.
Preferred examples of the aliphatic polyamine include linear or branched aliphatic polyamines having 3 to 11 nitrogen atoms, such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine. Branched polyamines are structural isomers of linear polyamines and have one or more tertiary amino groups. A mixture of two or more types of aliphatic polyamines may be used. The number of nitrogen atoms in the aliphatic polyamine is preferably 3 to 6, particularly preferably 4 to 6.
The above fatty acid may be a straight chain fatty acid or a branched chain fatty acid. Preferred examples of straight chain fatty acids include enanthic acid, caproic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, myristoleic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, vaccenic acid, and elaidin. acids, linoleic acid, linolenic acid, eleostearic acid, stearidonic acid, arachidic acid, gadoleic acid, eicosenoic acid, eicosapentaenoic acid, behenic acid, erucic acid, sardine acid, docosahexaenoic acid, lignoceric acid, nisic acid, and these acids. Mixtures and the like can be mentioned. Fatty acids derived from natural oils and fats may be used as a mixture containing two or more of the above fatty acids. Examples of fatty acids derived from natural oils include coconut oil fatty acids, palm kernel oil fatty acids, palm oil fatty acids, tung oil fatty acids, tall oil fatty acids, corn oil fatty acids, rapeseed oil fatty acids, olive oil fatty acids, sesame oil fatty acids, soybean oil fatty acids, and rice bran oil fatty acids. Examples include oil fatty acids, sunflower oil fatty acids, castor oil fatty acids, linseed oil fatty acids, fish oil fatty acids, beef tallow fatty acids, hydrogenated products thereof, and mixtures thereof.
Preferred examples of branched chain fatty acids include branched chain fatty acids having a tertiary or quaternary carbon atom (ie, branching) at the α, β, or γ position of the carbonyl carbon. In one embodiment, the branched chain fatty acid has a tertiary or quaternary carbon atom in the alpha or beta position of the carbonyl carbon. In one embodiment, the branched chain fatty acid has a tertiary or quaternary carbon atom alpha to the carbonyl carbon. A preferable example of such a branched chain fatty acid is a branched chain fatty acid represented by the following general formula (11).

(In general formula (11), f is an integer of 0 to 2, preferably 0 or 1, more preferably 0; R ¹⁶ is a linear or branched chain having 3 to 19 carbon atoms, preferably 4 to 19 carbon atoms) is a chain alkyl group; R ¹⁷ is a straight chain or branched alkyl group having 1 to 10 carbon atoms, preferably 2 to 10 carbon atoms; R ¹⁸ is a hydrogen atom or a straight chain or branched chain having 1 to 6 carbon atoms; Alkyl group, preferably a hydrogen atom; (number of carbon atoms in R ¹⁶ ) ≧ (number of carbon atoms in R ¹⁷ ) ≧ (number of carbon atoms in R ¹⁸ ); (number of carbon atoms in R ¹⁶ ) + (number of carbon atoms in R ¹⁷ ) ) + (number of carbon atoms in R ¹⁸ ) + k + 2 is equal to the total number of carbon atoms in the branched chain fatty acid.)
In one preferred embodiment, in the general formula (11), f is 0, ^R16 is a straight chain or branched alkyl group having 3 to 19 carbon atoms, and R17 is a straight chain or branched alkyl group having 1 to 10 carbon atoms. , R ¹⁸ may be a hydrogen atom. Preferred examples of the branched chain fatty acid represented by the general formula (11) include 2-ethylhexanoic acid, 2-butyloctanoic acid, 2-decyltetradecanoic acid, 5,7,7-trimethyl-2-(1,3 , 3-trimethylbutyl)octanoic acid (also known as isostearic acid).
Specific examples of fatty acid amide friction modifiers include lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, oleic acid amide, coconut oil fatty acid amide, synthetic mixed fatty acid amide having 12 to 13 carbon atoms, and the like. be able to.

Other examples of amide friction modifiers include hydrazides and ureides of fatty acids having 7 to 30 carbon atoms; aliphatic semicarbazides, aliphatic ureas, and aliphatic allophanes having alkyl or alkenyl groups having 7 to 30 carbon atoms. Examples include acid amides; and derivatives (modified products) thereof. Examples of derivatives (modified products) of amide friction modifiers include boron-modified products obtained by reacting the above-mentioned amide compounds with boric acid or boric acid salts. In these compounds, preferable examples of fatty acids having 7 to 30 carbon atoms include the fatty acids described above in connection with fatty acid amide friction modifiers, and preferable examples of alkenyl or alkenyl groups having 7 to 30 carbon atoms. may include alkyl or alkenyl groups corresponding to the fatty acids described above in connection with fatty acid amide friction modifiers. In this specification, "an alkyl or alkenyl group corresponding to a fatty acid" refers to an aliphatic alcohol (R ¹⁹ -CH ₂ -OH) obtained by reducing the carboxy group of a fatty acid (R ¹⁹ -CO ₂ H). means an alkyl or alkenyl group (R ¹⁹ --CH ₂ -- group) obtained by removing a hydroxy group from . In the above explanation, "reducing a carboxy group" and "removing a hydroxy group" refer to conceptual operations, and "an alkyl or alkenyl group corresponding to a fatty acid" does not necessarily mean a fatty acid as explained above. does not mean you have to get it.

Examples of fatty acid hydrazide friction modifiers include condensation products of fatty acids having 7 to 30 carbon atoms, preferably linear fatty acids, and unsubstituted or aliphatic substituted hydrazines; and acid-modified derivatives thereof (e.g., the condensation products). Examples include boron-modified products obtained by reacting boric acid with boric acid or boric acid salts, etc.). Preferred examples of fatty acids include those described above in connection with fatty acid amide friction modifiers.
Specific examples of fatty acid hydrazide friction modifiers include lauric acid hydrazide, tridecanoic acid hydrazide, myristic acid hydrazide, pentadecanoic acid hydrazide, palmitic acid hydrazide, heptadecanoic acid hydrazide, stearic acid hydrazide, oleic acid hydrazide, erucic acid hydrazide, etc. I can do it.

Examples of aliphatic urea friction modifiers include linear or branched (preferably linear) carbon atoms having 7 to 30, preferably 10 to 30, or 12 to 24, or 12 to 20, or 12 to 18 carbon atoms. Examples include aliphatic urea compounds having an alkyl or alkenyl group, and acid-modified derivatives thereof (for example, boron-modified products obtained by reacting the urea compound with boric acid or a boric acid salt). Preferred examples of alkenyl or alkenyl groups having 7 to 30 carbon atoms include alkyl or alkenyl groups corresponding to the fatty acids described above in connection with fatty acid amide friction modifiers.
Specific examples of aliphatic urea friction modifiers include dodecyl urea, tridecyl urea, tetradecyl urea, pentadecyl urea, hexadecyl urea, heptadecyl urea, octadecyl urea, and oleyl urea.

Other examples of amide friction modifiers include amide compounds of aliphatic hydroxy acids having hydroxy-substituted alkyl or alkenyl groups having 1 to 30 carbon atoms. The amide compound can be obtained, for example, as a condensation product of the aliphatic hydroxy acid and an aliphatic primary or secondary amine compound or an aliphatic primary or secondary alkanolamine compound. The number of carbon atoms in the hydroxy-substituted alkyl or alkenyl group of the aliphatic hydroxy acid is preferably 1 to 10, more preferably 1 to 4, and in one embodiment is 1 or 2. The aliphatic hydroxy acid is preferably a straight chain aliphatic α-hydroxy acid, and in one embodiment is glycolic acid. The above amine compound and alkanolamine compound preferably have an aliphatic hydrocarbon group having 1 to 30 carbon atoms, more preferably 10 to 30 carbon atoms, or 12 to 24 carbon atoms, or 12 to 20 carbon atoms, or 12 to 18 carbon atoms. The aliphatic hydrocarbon group is preferably a straight chain saturated aliphatic hydrocarbon group.

Other examples of amide friction modifiers include amide compounds of fatty acids having 7 to 30 carbon atoms and amino acids (N-acylated amino acid friction modifiers). Preferred examples of fatty acids include those described above in connection with fatty acid amide friction modifiers. Preferred examples of amino acids include N-methyl amino acids such as N-methylglycine, N-methyl-β-alanine, N-methylalanine, N-methylvaline, N-methylleucine, and N-methylisoleucine. Among these, N-methylglycine or N-methyl-β-alanine is particularly preferred.
Specific examples of N-acylated amino acid friction modifiers include N-acylated N-methylglycine (for example, N-oleoyl-N-methylglycine, etc.), N-acylated-N-methyl-β-alanine ( For example, N-oleoyl-N-methyl-β-alanine, etc.) can be mentioned.

Examples of aliphatic imide friction modifiers include succinimide having a linear or branched alkyl or alkenyl group having 6 to 30 carbon atoms; and its carboxylic acid, boric acid, phosphoric acid, or sulfuric acid. Modified products can be mentioned.
Examples of succinimide-based friction modifiers include bissuccinimide compounds and monosuccinimide compounds having an alkyl or alkenyl group having 8 to 30 carbon atoms, and derivatives (modified products) thereof. Such a succinimide compound is represented by, for example, the following general formula (12) or (13).

In general formulas (12) and (13), R ²⁰ and R ²¹ each independently represent an alkyl or alkenyl group having 8 to 30 carbon atoms, preferably 12 to 22 carbon atoms, or 12 to 18 carbon atoms. R ²² and R ²³ each independently represent an alkylene group having 1 to 4 carbon atoms, preferably an alkylene group having 2 to 3 carbon atoms, or an ethylene group. R ²⁴ represents a hydrogen atom or an alkyl or alkenyl group having 1 to 30 carbon atoms, preferably a hydrogen atom. g represents an integer of 1 to 7, preferably 1 to 4, or 1 to 3. h represents an integer of 1 to 7, preferably 1 to 5, or 2 to 5, or 2 to 4.

There are no particular restrictions on the method for producing a succinimide compound that can be used as a succinimide friction modifier. For example, an alkyl or alkenyl succinic acid having an alkyl or alkenyl group having 8 to 30 carbon atoms, preferably 12 to 22 carbon atoms, or an anhydride thereof, a polyamine, an N-monoC _1-30 alkylated product or an N-monoC The above succinimide compound can be obtained as a condensation product by reaction with a _1-30 alkenylated compound or a mixture thereof. As the succinimide friction modifier, the condensation product may be used as it is, or the condensation product may be converted into a derivative (modified product) described below. The condensation product of alkyl or alkenyl succinic acid or its anhydride and a polyamine may be a bis-type succinimide (see general formula (12)) in which both ends of the polyamine chain are imidized, It may be a monotype succinimide in which only one end of the polyamine chain is imidized (see general formula (13)), or a mixture thereof. Here, examples of polyamines include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and mixtures thereof, and polyamine raw materials containing one or more selected from these are preferably used. be able to. The polyamine raw material may or may not further contain ethylenediamine, but from the viewpoint of improving the performance of the condensation product or its derivative as a friction modifier, the content of ethylenediamine in the polyamine raw material should be It is preferably 0 to 10% by mass, more preferably 0 to 5% by mass based on the total amount of raw materials. As the N-mono C _1-30 alkylated polyamine, an N-mono C _1-30 alkylated polyamine having a C _1-30 alkyl group on the nitrogen atom at the chain end of the polyamine can be preferably used. As the N-mono C _1-30 alkenylated polyamine, an N-mono C _1-30 alkenylated polyamine having a C 1-30 alkenyl group on the nitrogen atom at the chain end of the polyamine can be preferably used. In this specification, "C _ij " (i and j are integers) means that the number of carbon atoms is i or more and j or less.

Examples of derivatives (modified products) of succinimide compounds that can be used as succinimide-based friction modifiers include boric acid, phosphoric acid, carboxylic acid having 1 to 20 carbon atoms, Examples include modified compounds obtained by reacting with one or more selected from .

Component (E) comprises (E1) one or more aliphatic hydrocarbyl groups having 8 to 30 carbon atoms and/or one or more aliphatic hydrocarbyl carbonyl groups having 8 to 30 carbon atoms, one or more amide bonds and and/or one or more imide bonds in one molecule, and the aliphatic hydrocarbyl carbonyl group may constitute a part of the amide bond and/or imide bond. It is preferable to include a nitrogen-containing compound (hereinafter sometimes referred to as "component (E1)"). Preferred examples of aliphatic hydrocarbyl groups include alkyl or alkenyl groups corresponding to the fatty acids described above in connection with the fatty acid amide friction modifiers. Preferred examples of the aliphatic hydrocarbylcarbonyl group include aliphatic acyl groups corresponding to the fatty acids described above in connection with the fatty acid amide friction modifier. In this specification, the term "aliphatic acyl group corresponding to a fatty acid" refers to an aliphatic acyl group (R ¹⁹ -CO- group) obtained by removing an -OH group from a fatty acid (R ¹⁹ -CO ₂ H). means. Component (E) may consist of component (E1), or may contain component (E1) and one or more other oil-based friction modifiers.

In one embodiment, component (E) preferably contains an amine friction modifier. The amine friction modifier may be used in combination with component (E1), for example. Examples of amine friction modifiers include linear or branched alkyl or alkenyl groups having 7 to 30 carbon atoms, preferably 10 to 30 carbon atoms, or 12 to 24 carbon atoms, more preferably 12 to 20 carbon atoms, preferably straight chain alkyl groups. or an aliphatic monoamine having an alkenyl group; a straight or branched alkyl or alkenyl group having 10 to 30 carbon atoms, preferably 12 to 24 carbon atoms, more preferably 12 to 20 carbon atoms, preferably a straight chain alkyl or alkenyl group , aliphatic polyamines; and alkylene oxide adducts of these aliphatic amines. Preferred examples of the alkyl or alkenyl groups mentioned above include those corresponding to the fatty acids described above in connection with fatty acid amide friction modifiers. A preferred form of the amine-based friction modifier is an alkyl or alkenyl dialkanolamine represented by the following general formula (14).

In general formula (14), R ²⁵ represents an alkyl or alkenyl group corresponding to the fatty acid described above in connection with the fatty acid amide friction modifier. i and j each independently represent an integer of 1 to 4, preferably an integer of 2 to 4, or an integer of 2 to 3, and may be 2 in one embodiment.

Examples of fatty acid ester friction modifiers include linear or branched (preferably linear) carbon atoms having 7 to 30, preferably 10 to 30, or 12 to 24, or 12 to 20, or 12 to 18 carbon atoms. Fatty acid and aliphatic monohydric alcohol (e.g. methanol, ethanol, etc.) or aliphatic polyhydric alcohol (e.g. glycerin, trimethylolmethane, trimethylolethane, trimethylolpropane, pentaerythritol, erythritol, diglycerin, sorbitan, adonitol, Examples include esters with arabitol, xylitol, allose, talose, triglycerin, dipentaerythritol, sorbitol, mannitol, iditol, inositol, dulcitol, polyglycerin, etc.). Preferred examples of fatty acids include those described above in connection with fatty acid amide friction modifiers.

Examples of fatty acid metal salt-based friction modifiers include linear or branched, preferably linear, carbon atoms having 7 to 30, preferably 10 to 30, or 12 to 24, or 12 to 20, or 12 to 18 carbon atoms. Examples include alkaline earth metal salts (magnesium salts, calcium salts, etc.) and zinc salts of fatty acids. Preferred examples of fatty acids include those described above in connection with fatty acid amide friction modifiers.

Examples of aliphatic alcohol friction modifiers include linear or branched, preferably linear, carbon atoms having 7 to 30 carbon atoms, preferably 10 to 30 carbon atoms, or 12 to 24 carbon atoms, or 12 to 20 carbon atoms, or 12 to 18 carbon atoms. Mention may be made of alkyl or alkenyl alcohols. Preferred examples of alkyl or alkenyl groups include those corresponding to the fatty acids described above in connection with fatty acid amide friction modifiers.

The preferred content of component (E) in the lubricating oil composition may vary depending on the type of compound, but may be, for example, 0.10 to 3.00% by mass.

For example, when the component (E) includes the component (E1), the content of the component (E1) is preferably 0.000% based on the total amount of the lubricating oil composition, from the viewpoint of improving the stick slip prevention (shudder prevention) property of the wet clutch. 10% by mass or more, or 0.40% by mass or more, or 0.80% by mass or more, and preferably 3.00% by mass or less, or 2. .00% by mass or less, or 1.50% by mass or less, and in one embodiment, 0.10 to 3.00% by mass, or 0.40 to 2.00% by mass, or 0.80 to 1.50% by mass. It can be mass %.

For example, when component (E) includes component (E1) and an oil-based friction modifier other than the component (E1), the content of the oil-based friction modifier other than the component (E1) is From the viewpoint of improving anti-judder properties, it is preferably 0.001% by mass or more, or 0.005% by mass or more, or 0.010% by mass or more based on the total amount of the lubricating oil composition, and also reduces the transmission torque capacity of the wet clutch. From the viewpoint of ensuring a higher level of , or 0.005 to 0.080% by weight, or 0.010 to 0.050% by weight.

<(F) Poly(meth)acrylate viscosity index improver>
In one preferred embodiment, the lubricating oil composition of the present invention comprises one or more poly(meth)acrylates (hereinafter sometimes referred to as "component (F)") having a weight average molecular weight of 10,000 to 100,000. ). In addition, in this specification, "(meth)acrylate" means "acrylate and/or methacrylate." As component (F), one type of poly(meth)acrylate may be used alone, or a mixture of two or more types of poly(meth)acrylates may be used.

As component (F), either a dispersed polyalkyl (meth)acrylate or a non-dispersed polyalkyl (meth)acrylate may be used. From the viewpoint of further increasing the transmission torque capacity and engagement performance of the wet clutch, dispersed polyalkyl (meth)acrylate can be more preferably used.

The weight average molecular weight of component (F) is preferably 10,000 or more, or 20,000 or more, or 30,000 or more from the viewpoint of improving the low-temperature fluidity of the lubricating oil composition, and from the viewpoint of improving the shear stability. Preferably, it is 100,000 or less, or 70,000 or less, or 50,000 or less, and in one embodiment, 10,000 to 100,000, or 20,000 to 70,000, or 30,000 to 50, It can be 000. When component (F) is a mixture of a plurality of poly(meth)acrylates, it is preferable that the weight average molecular weight of each poly(meth)acrylate is within the above range.

Component (F) acts as a viscosity index improver and/or pour point depressant. The content (total content) of component (F) in the lubricating oil composition is preferably 0.5% by mass as a resin content based on the total amount of the lubricating oil composition, from the viewpoint of improving the low-temperature fluidity of the lubricating oil composition. or more, or 1.0 mass% or more, or 2.0 mass% or more, and preferably 6.0 mass% or less, or 5.0 mass% or less, or 4.0 mass%, from the viewpoint of increasing shear stability. or less, and in one embodiment may be from 0.5 to 6.0% by weight, or from 1.0 to 5.0, or from 2.0 to 4.0. Note that in this specification, the resin component means a polymer component having a molecular weight of 1,000 or more.

<(G) Antioxidant>
In one preferred embodiment, the lubricating oil composition contains one or more amine antioxidants and/or one or more phenolic antioxidants (hereinafter sometimes referred to as "component (G)"). ). As component (G), one type of compound may be used alone, or two or more types of compounds may be used in combination.

Examples of amine-based antioxidants include aromatic amine-based antioxidants and hindered amine-based antioxidants. Examples of aromatic amine antioxidants include primary aromatic amine compounds such as alkylated α-naphthylamine; and diphenylamine, alkylated diphenylamine, phenyl-α-naphthylamine, alkylated phenyl-α-naphthylamine, and phenyl. - Secondary aromatic amine compounds such as β-naphthylamine and alkylated phenyl-β-naphthylamine; As the aromatic amine antioxidant, alkylated diphenylamine, alkylated phenyl-α-naphthylamine, or a combination thereof can be preferably used.

Examples of phenolic antioxidants include 4,4'-methylenebis(2,6-di-tert-butylphenol); 4,4'-bis(2,6-di-tert-butylphenol); -bis(2-methyl-6-tert-butylphenol); 2,2'-methylenebis(4-ethyl-6-tert-butylphenol); 2,2'-methylenebis(4-methyl-6-tert-butylphenol); 4,4'-butylidenebis(3-methyl-6-tert-butylphenol); 4,4'-isopropylidenebis(2,6-di-tert-butylphenol); 2,2'-methylenebis(4-methyl-6 -nonylphenol); 2,2'-isobutylidenebis(4,6-dimethylphenol); 2,2'-methylenebis(4-methyl-6-cyclohexylphenol); 2,6-di-tert-butyl-4 -Methylphenol; 2,6-di-tert-butyl-4-ethylphenol; 2,4-dimethyl-6-tert-butylphenol; 2,6-di-tert-butyl-4-(N,N'-dimethyl 4,4'-thiobis(2-methyl-6-tert-butylphenol); 4,4'-thiobis(3-methyl-6-tert-butylphenol); 2,2'-thiobis(4- methyl-6-tert-butylphenol); bis(3-methyl-4-hydroxy-5-tert-butylbenzyl) sulfide; bis(3,5-di-tert-butyl-4-hydroxybenzyl) sulfide; 3-( Examples include 3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid esters; 3-methyl-5-tert-butyl-4-hydroxyphenol fatty acid esters. Examples of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid esters include octyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; decyl -3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; Dodecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; Tetradecyl-3-(3, 5-di-tert-butyl-4-hydroxyphenyl)propionate; hexadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; octadecyl-3-(3,5-di-tert- Butyl-4-hydroxyphenyl)propionate; Pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; 2,2'-thio-diethylenebis[3-(3, 5-di-tert-butyl-4-hydroxyphenyl)propionate], and the like.

When the lubricating oil composition contains an amine antioxidant as component (G), the content is preferably 0.1 to 1.0 based on the total amount of the lubricating oil composition from the viewpoint of thermal oxidative stability. The amount is preferably 0.2 to 1.0% by weight, and even more preferably 0.3 to 0.9% by weight.
When the lubricating oil composition contains a phenolic antioxidant as component (G), the content is preferably 0.1 to 1.0 based on the total amount of the lubricating oil composition from the viewpoint of thermal oxidative stability. The amount is preferably 0.2 to 0.9% by weight, and even more preferably 0.3 to 0.8% by weight.

<Other additives>
In one embodiment, the lubricating oil composition includes an anti-wear agent or extreme pressure agent other than the component (A) and the component (B), a polymer other than the component (F), an oil-soluble organic molybdenum compound, and a component other than the component (A). It may further contain one or more selected from corrosion inhibitors, rust preventives, metal deactivators other than component (A), seal swelling agents, antifoaming agents, demulsifiers, and colorants.

Examples of antiwear agents or extreme pressure agents other than component (A) and component (B) include sulfur-based additives that do not fall under component (A), such as disulfides, polysulfides, sulfurized olefins, and sulfurized oils and fats. (Sulfur-based extreme pressure agents); thiophosphites, dithiophosphites, trithiophosphites, thiophosphates, dithiophosphates, trithiophosphates, tetrathiophosphates, etc. Examples include sulfur-containing phosphorus compounds (phosphorus-sulfur anti-wear agents). The lubricating oil composition may or may not contain anti-wear agents or extreme pressure agents other than the components (A) and (B). When the lubricating oil composition contains an anti-wear agent or an extreme pressure agent other than the components (A) and (B), the total content is preferably more than 0% by mass based on the total amount of the lubricating oil composition. It is less than .020% by mass, or more than 0% by mass and less than 0.015% by mass, or more than 0% by mass and less than 0.010% by mass.

As the polymer other than component (F), polymers other than poly(meth)acrylate that are known as additives for lubricating oils can be used. Examples of polymers other than component (F) include ethylene-α-olefin copolymers and their hydrides, copolymers of α-olefins and ester monomers having polymerizable unsaturated bonds, and polyisobutylene and its hydrides. Examples include hydrides, hydrides of styrene-diene copolymers, styrene-maleic anhydride copolymers, ethylene-vinyl acetate copolymers and hydrides thereof, and polyalkylstyrenes. Among these, ethylene-α-olefin copolymers or hydrides thereof can be preferably used. In one embodiment, an ethylene-propylene copolymer or a hydride thereof can be preferably used as the ethylene-α-olefin copolymer or a hydride thereof. In one embodiment, the weight average molecular weight of the polymer other than component (F) may be, for example, 2,000 to 30,000, preferably 5,000 to 15,000. The lubricating oil composition may or may not contain polymers other than component (F). When the lubricating oil composition contains a polymer other than component (F), the content thereof is preferably more than 0% by mass and less than 5.0% by mass, or more than 4.0% by mass, based on the total amount of the lubricating oil composition. It is less than 0% by mass, or more than 0% by mass and less than 2.0% by mass.

Examples of oil-soluble organic molybdenum compounds include organic molybdenum compounds containing sulfur and organic molybdenum compounds containing no sulfur as a constituent element. Examples of organic molybdenum compounds containing sulfur include molybdenum dithiocarbamates; molybdenum dithiophosphate compounds; molybdenum compounds (e.g., molybdenum oxides such as molybdenum dioxide and molybdenum trioxide, orthomolybdic acid, paramolybdic acid, and (poly)sulfides. Molybdic acid such as molybdic acid, molybdate salts such as metal salts and ammonium salts of molybdic acid, molybdenum sulfide such as molybdenum disulfide, molybdenum trisulfide, molybdenum pentasulfide, and molybdenum polysulfide, molybdic acid sulfide, and molybdic acid sulfide. metal salts or amine salts, molybdenum halides such as molybdenum chloride, etc.) and sulfur-containing organic compounds (e.g., alkyl(thio)xanthates, thiadiazole, mercaptothiadiazole, thiocarbonates, tetrahydrocarbylthiuram disulfide, bis(di( thio)hydrocarbyl dithiophosphonate) disulfide, organic (poly)sulfide, sulfurized ester, etc.) or complexes with other organic compounds; and sulfur-containing molybdenum compounds such as molybdenum sulfide and molybdic acid sulfide, and alkenylsuccinic acid. Examples include complexes with imides. Note that the organic molybdenum compound may be a mononuclear molybdenum compound or a polynuclear molybdenum compound such as a dinuclear molybdenum compound or a trinuclear molybdenum compound. Examples of organic molybdenum compounds that do not contain sulfur as a constituent element include molybdenum-amine complexes, molybdenum-succinimide complexes, molybdenum salts of organic acids, and molybdenum salts of alcohols.
The lubricating oil composition may or may not contain an oil-soluble organic molybdenum compound. When the lubricating oil composition contains an oil-soluble organic molybdenum compound, the content thereof is preferably from more than 0% by mass to less than 0.05% by mass, or from more than 0% by mass to 0% by mass, based on the amount of molybdenum based on the total amount of the composition. Less than .03% by weight, or more than 0% by weight and less than 0.02% by weight.

As the corrosion inhibitor other than the component (A), for example, known corrosion inhibitors such as benzotriazole-based, tolyltriazole-based, and imidazole-based compounds can be used. When the lubricating oil composition contains a corrosion inhibitor other than component (A), the content is usually 0.005 to 5% by mass based on the total amount of the lubricating oil composition.

As the rust preventive agent, known rust preventive agents such as petroleum sulfonate, alkylbenzene sulfonate, dinonylnaphthalene sulfonate, alkenyl succinate, and polyhydric alcohol ester can be used. When the lubricating oil composition contains a rust inhibitor, its content is usually 0.005 to 5% by mass based on the total amount of the lubricating oil composition.

Examples of metal deactivators other than component (A) include imidazoline, pyrimidine derivatives, mercaptobenzothiazole, benzotriazole and its derivatives, 2-(alkyldithio)benzimidazole, and β-(o-carboxybenzylthio). Known metal deactivators such as propionitrile can be used. When the lubricating oil composition contains a metal deactivator other than component (A), the content is usually 0.005 to 1% by mass based on the total amount of the lubricating oil composition.

As the seal swelling agent, compounds commonly used as seal swelling agents for lubricating oils can be used without particular limitation, and examples include ester-based, sulfur-based, aromatic-based seal swelling agents, and the like. For example, known seal swelling agents such as alcohols, alkylbenzenes, substituted sulfolanes, mineral oils, etc., which cause swelling of the elastomeric material, can be used.
The alcohol-based seal swell agent is a linear alkyl alcohol with low volatility, and preferred examples thereof include decyl alcohol, tridecyl alcohol, and tetradecyl alcohol. In this specification, if the alcohol-based seal swelling agent also corresponds to component (E), the content of the alcohol-based seal swelling agent shall also contribute (count) to the content of component (E). do.
Examples of alkylbenzenes that can be used as seal swelling agents include dodecylbenzene, tetradecylbenzene, dinonylbenzene, di(2-ethylhexyl)benzene, and the like.
An example of a substituted sulfolane that can be used as a seal swelling agent is a substituted sulfolane compound represented by the following general formula (15).

In general formula (15), R ²⁶ is a hydrocarbon group having 4 or more carbon atoms, preferably an alkyl or alkenyl group having 4 to 25 carbon atoms, more preferably 4 to 10 carbon atoms. R ²⁷ and R ²⁸ are each a hydrogen atom or a (preferably linear) alkyl group having 7 or less carbon atoms, preferably one of R ²⁷ and R ²⁸ is a hydrogen atom, and the other (preferably R ²⁸ ) is a hydrogen atom. or a methyl group, more preferably both R ²⁷ and R ²⁸ are hydrogen atoms. X ¹ is an oxygen atom or a sulfur atom, preferably an oxygen atom.
Mineral oils that can be used as seal swell agents are typically low viscosity mineral oils with high naphthenic or aromatic content.
The lubricating oil composition may or may not contain a seal swelling agent; however, when the lubricating oil composition contains a seal swelling agent, the content thereof is usually 0.0000% based on the total amount of the composition. 01 to 3.0% by mass.

As the antifoaming agent, for example, known antifoaming agents such as silicone, fluorosilicone, and fluoroalkyl ether can be used. When the lubricating oil composition contains an antifoaming agent, its content is usually 0.0005 to 1% by mass based on the total amount of the lubricating oil composition.

As the demulsifier, known demulsifiers such as polyalkylene glycol nonionic surfactants can be used. When the lubricating oil composition contains a demulsifier, its content is usually 0.005 to 5% by mass based on the total amount of the lubricating oil composition.

As the colorant, for example, known colorants such as azo compounds can be used.

<Lubricating oil composition>
The kinematic viscosity at 100° C. of the lubricating oil composition is 6.2 mm ² /s or less from the perspective of increasing energy saving, and preferably 4.5 mm from the perspective of further increasing wear resistance, seizure resistance, and fatigue life. ² /s or more, or 5.0 mm ² /s or more, or 5.5 mm ² /s or more, and in one embodiment, 4.5 to 6.2 mm ² /s, or 5.0 to 6.2 mm ² /s, or 5.5-6.2 mm ² /s.

The kinematic viscosity at 40° C. of the lubricating oil composition is preferably 35.0 mm ² /s or less, 32.5 mm ² /s or less, or 30.0 mm ² /s or less from the viewpoint of further improving energy saving properties.

The viscosity index of the lubricating oil composition is preferably 155 or more, or 156 from the viewpoint of improving the temperature-viscosity characteristics of the composition and further increasing energy saving, wear resistance, seizure resistance, and fatigue life. or 157 or more.

The sulfur content in the lubricating oil composition is 0.050% by mass or less, preferably 0.048% by mass based on the total amount of the composition, from the viewpoint of improving wear resistance and the transmission torque capacity and engagement performance of the wet clutch. % by mass or less, or 0.045% by mass or less. In addition, the sulfur content in the lubricating oil composition is preferably 0.005% by mass or more, or 0.010% by mass based on the total amount of the composition, from the viewpoint of further improving gear lubrication performance (seizure resistance and fatigue resistance). % by mass or more, or 0.015% by mass or more. In one embodiment, the sulfur content in the lubricating oil composition is 0.005% to 0.050% by mass, or 0.010 to 0.048% by mass, or 0.015 to 0.045% by mass. It can be mass %.

From the viewpoint of further increasing wear resistance and seizure resistance, the phosphorus content in the lubricating oil composition is preferably 0.010% by mass or more, 0.025% by mass or more, or 0. It is .030% by mass or more. In addition, the phosphorus content in the lubricating oil composition is preferably based on the total amount of the composition, from the viewpoint of further increasing seizure resistance, fatigue resistance, and oxidation stability, and from the viewpoint of further increasing the transmission torque capacity of a wet clutch. is 0.100% by mass or less, or 0.085% by mass or less, or 0.075% by mass or less. In one embodiment, the content of phosphorus in the lubricating oil composition is from 0.010 to 0.100% by mass, or from 0.025 to 0.085% by mass, or from 0.030 to 0.030% by mass based on the total amount of the composition. It can be 0.75% by weight.

The ratio MS/MP of the sulfur content MS (unit: mass %) in the lubricating oil composition to the phosphorus content MP (unit: mass %) in the lubricating oil composition is determined from the viewpoint of improving wear resistance and seizure resistance. It is 1.00 or less, preferably 0.95 or less, or 0.90 or less. Further, the ratio MS/MP is preferably 0.30 or more, 0.35 or more, or 0.40 or more from the viewpoint of further improving seizure resistance, fatigue resistance, oxidation stability, and transmission torque capacity of the wet clutch. It is. In one embodiment, the ratio MS/MP can be between 0.30 and 0.100, or between 0.35 and 0.95, or between 0.40 and 0.90.

The boron content in the lubricating oil composition is less than 0.030% by mass, preferably 0.029% by mass or less, based on the total amount of the composition, from the viewpoint of improving fatigue resistance. In addition, the boron content in the lubricating oil composition is preferably 0.010% by mass or more based on the total amount of the composition, from the viewpoint of further increasing wear resistance, seizure resistance, and transmission torque capacity of a wet clutch. . In one embodiment, the boron content in the lubricating oil composition may be 0.010% by mass or more and less than 0.030% by mass, or 0.010 to 0.029% by mass based on the total amount of the composition. .

The calcium content in the lubricating oil composition is determined based on the total amount of the composition, from the viewpoint of further improving wear resistance, seizure resistance, oxidation stability, and the transmission torque capacity and engagement performance of wet clutches. It is preferably 0.008% by mass or more, or 0.009% by mass or more. In addition, the calcium content in the lubricating oil composition is determined from the viewpoint of making it easier to keep the ratio MB/MCa of boron content (MB) to calcium content (MCa) in the composition below the upper limit value, which will be described later. , preferably 0.050% by mass or less, or 0.045% by mass or less, or 0.040% by mass or less, based on the total amount of the composition. In one embodiment, the content of component (C) is 0.008 to 0.050% by mass, or 0.008 to 0.045% by mass, or 0.009 to 0.009% by mass as calcium content based on the total amount of the composition. .040% by weight.

The ratio MB/MCa of the boron content MB (unit: mass %) in the lubricating oil composition to the calcium content MCa (unit: mass %) in the lubricating oil composition determines wear resistance, seizure resistance, and wet clutch. From the viewpoint of increasing the transmission torque capacity, it is 0.800 or more, preferably 0.805 or more, or 0.810 or more. Further, the ratio MB/MCa is 1.200 or less, preferably 1.170 or less, from the viewpoint of improving wear resistance, seizure resistance, fatigue resistance, oxidation stability, and the transmission torque capacity and engagement performance of the wet clutch. or 1.160 or less. In one embodiment, the ratio MB/MCa can be from 0.800 to 1.200, or from 0.805 to 1.170, or from 0.810 to 1.160.

From the perspective of further increasing wear resistance, seizure resistance, and fatigue life in the endurance stage, a lubricant shear stability test in accordance with JPI-5S-29-88 revealed that the lubricant composition was The kinematic viscosity of the composition at 100° C. after being irradiated with ultrasonic waves with a swing width of 28 μm for 10 hours is preferably 5.5 mm ² /s or more.

(Application)
The lubricating oil composition of the present invention can be preferably used for the lubrication of transmissions equipped with wet clutches (for example, automatic transmissions, continuously variable transmissions, etc.), and can be used, for example, for the lubrication of these transmissions installed in automobiles. It can be preferably used.

Hereinafter, the present invention will be explained in more detail based on Examples and Comparative Examples. However, the present invention is not limited to these examples.

<Examples 1 to 12 and Comparative Examples 1 to 8>
As shown in Tables 1 to 4, lubricating oil compositions of the present invention (Examples 1 to 12) and comparative lubricating oil compositions (Comparative Examples 1 to 8) were prepared, respectively. In the table, in the item "Base oil composition", "mass%" means mass% based on the total amount of base oil (100 mass%), and in other items, "mass%" refers to the total amount of the lubricating oil composition. It means mass % based on the standard (100 mass %). Furthermore, "mass ppm" means mass ppm based on the total amount of the lubricating oil composition, and the expression "mass ppm/X" for element X means mass ppm based on the total amount of the composition as the amount of element X. do. Details of each component are as follows.

(Lubricant base oil)
O-1: API Group III base oil, kinematic viscosity (100°C): 3.883 mm ² /s, kinematic viscosity (40°C): 15.65 mm ² /s, viscosity index: 142, sulfur content: 4 mass ppm, % _CP : 92.5, % _CN : 7.5, % _CA : 0
O-2: API Group III base oil, kinematic viscosity (100°C): 6.208 mm ² /s, kinematic viscosity (40°C): 33.97 mm ² /s, viscosity index: 133, sulfur content: less than 10 mass ppm ,%C _P :80.6,%C _N :19.4,%C _A :0
O-3: API Group II base oil, kinematic viscosity (100°C): 3.12 mm ² /s, kinematic viscosity (40°C): 12.43 mm ² /s, viscosity index: 112, sulfur content: less than 10 mass ppm , %C _P : 75.1, %C _N : 24.9, %C _A : 0
O-4: API Group IV base oil (SpectraSyn (registered trademark) 6 manufactured by Exxon Mobil Chemical), kinematic viscosity (100°C): 5.8 mm ² /s, kinematic viscosity (40°C): 31 mm ² /s, viscosity Index: 138, Pour point: -57℃, Flash point: 246℃
O-5: API Group IV base oil (SpectraSyn (registered trademark) 4 manufactured by Exxon Mobil Chemical), kinematic viscosity (100°C): 4.1 mm ² /s, kinematic viscosity (40°C): 19 mm ² /s, viscosity Index: 126, pour point: -66℃, flash point 220℃

((A) Sulfur-based compound)
A-1: Thiadiazole compound (a=b=2, R ¹ =R ² =nonyl group in general formula (1)), sulfur content 35.0% by mass
A-2 ^* : Sulfurized olefin/sulfurized oil/fat mixture, sulfur content 30.5% by mass

((B) Phosphorus compound)
B-1: Diphenyl hydrogen phosphite (phosphite diester in which R ³ =R ⁴ = phenyl group in general formula (4); includes tautomer), phosphorus content 13.2% by mass
B-2 ^* : Dithiophosphate ester, phosphorus content 9.0% by mass, sulfur content 19.4% by mass

((C) Calcium-based cleaning agent)
C-1: Calcium sulfide phenate detergent, base value 255 mgKOH/g, Ca content 0.25% by mass, sulfur content 3.5% by mass

((D) Succinimide dispersant)
D-1: Boron-containing succinimide ashless dispersant, nitrogen content 1.48% by mass, boron content 1.30% by mass
D-2: Non-boron modified succinimide ashless dispersant, nitrogen content 1.44% by mass

((E) Oil-based friction modifier)
E-1: Fatty acid amide friction modifier, condensation reaction product of isostearic acid and tetraethylenepentamine, nitrogen content 6.20% by mass, total base number (perchloric acid method) 81.0mgKOH/g
E-2: Aliphatic amine friction modifier, oleyl diethanolamine (R ²⁵ = oleyl group, i=j=2 in general formula (14))

(F) Poly(meth)acrylate: Dispersed poly(meth)acrylate, weight average molecular weight: 40,000

(G) Antioxidant: Amine antioxidant, diphenylamine

Other performance additives: seal swelling agent, antifoaming agent (dimethyl silicone, kinematic viscosity (25°C): 160,000mm ² /s)

(High-speed four-ball test)
For each of the lubricating oil compositions, the final non-seizure load (LNSL) was measured at a rotation speed of 1800 rpm by a high-speed four-ball test in accordance with JPI-5S-40-93. The results are shown in Tables 1-4. The higher the LNSL value measured in this test, the better the seizure resistance.
The wear resistance of each lubricating oil composition was evaluated by a high-speed four-ball test in accordance with JPI-5S-40-93. The wear scar diameter was measured after operating for 30 minutes at a rotational speed of 1200 rpm, a load of 392 N, and an oil temperature of 80°C. The results are shown in Tables 1-4. The smaller the wear scar diameter measured in this test, the better the wear resistance.

(FALEX seizure test)
The seizure resistance of each of the lubricating oil compositions was evaluated by a FALEX seizure test based on ASTM D3233 A method. A steel pin sandwiched between two stationary steel V-blocks was rotated at 290 rpm under an oil temperature of 110° C., and the load at which seizure occurred (seizure load) was measured. The results are shown in Tables 1-4. The higher the value of the seizure load measured in this test, the better the seizure resistance.

(Unisteel test)
Each of the lubricating oil compositions was tested using a Unisteel rolling fatigue tester (Triple High Temperature Rolling Fatigue Tester (TRF-1000/3-01H), manufactured by Tokyo Test Instruments Co., Ltd.) using a Unisteel test (British Petroleum Institute). The rolling fatigue life of the thrust bearing was measured using the following method: IP305/79). A test bearing in which one side of the bearing ring of a thrust needle bearing (NSK FNTA-2542C) was replaced with a flat test piece (material: SUJ2) was tested under the following conditions: load 7000N, surface pressure 2GPa, rotation speed 1450rpm, oil temperature 120℃. Below, the time until either the roller or the specimen suffered fatigue damage was measured. It was determined that fatigue damage occurred when the vibration acceleration of the test section reached 1.5 m/s ² as measured by a vibration accelerometer installed in the Unisteel rolling fatigue testing machine. The fatigue life was calculated as 50% life (L50: time at which the cumulative probability becomes 50%) using a Weibull plot from the time until fatigue damage in 10 repeated tests. The results are shown in Tables 1-4. The longer the 50% life measured in this test, the better the fatigue resistance.

(ISOT oxidation stability test)
The oxidation stability of each of the lubricating oil compositions was evaluated by an ISOT test based on JIS K2514. A test was conducted at an oil temperature of 165°C for 144 hours, and the increase in acid value (mgKOH/g) after the test was measured. The results are shown in Tables 1-4. The smaller the increase in acid value after the test, the better the oxidation stability.

(SAE No. 2 friction test: Evaluation of gear shift shock index)
For each of the lubricating oil compositions, SAE No. 2 test machine (manufactured by Shinko Zoki), a dynamic friction test was conducted in accordance with JASO M348:2002. After 10,000 cycles, the static friction coefficient μ _t and dynamic friction coefficient μ _d between the friction plate (NW461E material) and the steel plate were measured. The results are shown in Tables 1-4. The higher the static friction coefficient _μt means the larger the transmission torque capacity of the wet clutch. Further, the higher the dynamic friction coefficient μ _d , the higher the engagement performance of the wet clutch.

(Evaluation results)
The lubricating oil compositions of Examples 1 to 12 showed good results in terms of shear stability, seizure resistance, wear resistance, fatigue resistance, and oxidation stability, as well as the transmission torque capacity and engagement performance of wet clutches. showed that.
The composition of Comparative Example 1, in which the sulfur content in the composition was excessive and the ratio MS/MP of the sulfur content MS to the phosphorus content MP in the composition was excessive, had poor wear resistance and wet clutch properties. showed poor results in transmission torque capacity and fastening performance.
The composition of Comparative Example 2 containing a sulfur-based additive (sulfurized olefin/sulfurized fat mixture) that is not a thiadiazole compound in place of component (A) (thiadiazole compound) has excellent wear resistance, fatigue resistance, and oxidation stability. The result was poor performance, as well as the transmission torque capacity and engagement performance of wet clutches.
The composition of Comparative Example 3, in which the ratio MS/MP of the sulfur content MS to the phosphorus content MP in the composition was excessive, showed poor results in wear resistance and seizure resistance.
Contains a sulfur-containing phosphorus compound (dithiophosphate) in place of component (B) (non-sulfur-containing phosphorus compound), the sulfur content in the composition is excessive, and the sulfur content MS and phosphorus content MP in the composition The composition of Comparative Example 4, in which the ratio MS/MP was excessive, showed poor results in wear resistance, fatigue resistance, and oxidation stability, as well as in the transmission torque capacity and engagement performance of a wet clutch.
The composition of Comparative Example 5, in which component (D) did not contain a boron-containing succinimide dispersant and the ratio MB/MCa of boron content MB to calcium content MCa in the composition was too small, had poor wear resistance. It showed poor results in seizure resistance and transmission torque capacity of wet clutches.
The composition of Comparative Example 6, in which the ratio MB/MCa of boron content MB to calcium content MCa in the composition was excessive, had poor wear resistance, seizure resistance, oxidation stability, and transmission torque capacity of a wet clutch. and showed poor results in fastening performance.
The composition of Comparative Example 7, in which the ratio MB/MCa of boron content MB to calcium content MCa in the composition was excessive, showed poor results in fatigue resistance.

Claims

a lubricating base oil comprising one or more mineral base oils or one or more synthetic base oils, or a combination thereof;
(A) one or more thiadiazole compounds;
(B) one or more sulfur-free phosphorus compounds;
(C) one or more calcium-based detergents, including one or more calcium phenate detergents;
(D) one or more succinimide dispersants, including one or more boron-containing succinimide dispersants;
(E) one or more oil-based friction modifiers;
Contains
The sulfur content in the composition is 0.050% by mass or less based on the total amount of the composition,
The boron content in the composition is less than 0.030% by mass based on the total amount of the composition,
The kinematic viscosity at 100°C of the composition is 6.2 mm 2 /s or less,
The ratio MS/MP of the sulfur content MS (unit: mass %) in the composition to the phosphorus content MP (unit: mass %) in the composition is 1.00 or less,
The ratio MB/MCa of the boron content MB (unit: mass %) in the composition to the calcium content MCa (unit: mass %) in the composition is 0.80 to 1.20. A lubricating oil composition characterized by:
The lubricating oil composition according to claim 1, wherein the content of the component (A) is 0.010 to 0.050% by mass as a sulfur content based on the total amount of the composition.
The lubricating oil composition according to claim 1 or 2, wherein the content of the component (B) is 0.010 to 0.100% by mass as a phosphorus content based on the total amount of the composition.
The lubricating oil composition according to claim 1 or 2, wherein the boron content MB in the composition is 0.010% by mass or more and less than 0.030% by mass based on the total amount of the composition.
The lubricating oil composition according to claim 1 or 2, wherein the content of the component (C) is 0.008 to 0.040% by mass as calcium content based on the total amount of the composition.
The lubricating oil composition according to claim 1 or 2, wherein the content of the component (D) is 0.010% by mass or more and less than 0.030% by mass as a boron content based on the total amount of the composition.
Component (E) comprises (E1) one or more aliphatic hydrocarbyl groups having 8 to 30 carbon atoms and/or one or more aliphatic hydrocarbyl carbonyl groups having 8 to 30 carbon atoms, and one or more amide bonds. and/or one or more imide bonds in one molecule, and the aliphatic hydrocarbylcarbonyl group may constitute a part of the amide bond and/or imide bond. The lubricating oil composition according to claim 1 or 2, which contains 0.10 to 3.00% by mass of the acylated nitrogen-containing compound based on the total amount of the composition.
The lubricating oil composition according to claim 1 or 2, further comprising (F) one or more poly(meth)acrylates having a weight average molecular weight of 10,000 to 100,000.
(G) 0.01 to 1.00% by mass of one or more amine antioxidants and/or one or more phenolic antioxidants based on the total amount of the composition, claim 1 or 2. The lubricating oil composition described in .
The lubricating oil composition according to claim 1 or 2, wherein the lubricating oil base oil has a kinematic viscosity at 100°C of 4.2 mm 2 /s or more and a viscosity index of 120 or more.
The lubricating oil composition according to claim 1 or 2, wherein the lubricating oil composition has a viscosity index of 155 or more.
In a lubricating oil shear stability test in accordance with JPI-5S-29-88, the lubricating oil composition was irradiated with ultrasonic waves with a frequency of 10 kHz and a vibrator amplitude of 28 μm for 10 hours, and then the behavior of the composition at 100°C was determined. The lubricating oil composition according to claim 1 or 2, having a viscosity of 5.5 mm 2 /s or more.
The lubricating oil composition according to claim 1 or 2, which is used for lubrication of a transmission equipped with a wet clutch.